The present invention relates to a showcase in which a display room is provided over an insulating wall; a machine room containing a compressor and the like is provided under the insulating wall; a cooling room is provided in the insulating wall; and an evaporator and a cooling fan of a cooling unit are installed in the cooling room so that cold air heat-exchanged with the evaporator is circulated in the display room by the cooling fan.
In a conventional showcase of this kind, left, right, and rear transparent walls and a front transparent door (transparent wall) are attached to supporting columns standing at four corners of an insulating wall so that a display room surrounded by the transparent walls is provided over the insulating wall. In the insulating wall, a cooling room is provided in which an evaporator and a cooling fan of a cooling unit are disposed. Under the insulating wall, there is provided a machine room in which a compressor, a condenser and the like disposed. By operating the compressor and the like, the evaporator exerts a cooling function and the cooling fan serves to eject cold air from one side of the insulating wall and suck the cold air from the other side of the insulating wall. The cold air is thereby circulated into the display room to cool the interior of the display room to a predetermined temperature (e.g., see Japanese Patent Unexamined Publication No. hei 5-203332).
In such a showcase, angles are attached to four corners of a base that serves as the bottom of the machine room, and the angles hold the insulating wall. Supporting columns which vertically extend in the showcase are attached to four corners of the insulating wall. Thus, the machine room having a predetermined height is provided under the insulating wall. Over the insulating wall, there is provided the display room defined by the transparent walls attached to the supporting columns.
In the above-described construction, the insulating wall and further a top plate constituting a top surface of the machine room can not be fixed, unless the angles are attached to the four corners of the base. Therefore, the number of parts inevitably increases, and operation becomes complicated.
On the other hand, the transparent door is provided on the supporting columns to open and close the display room, and the transparent door is supported so as to be freely revolvable around the supporting column. Therefore, in the operation of opening or closing the transparent door, a strong force is imposed particularly on the column, and hence bending is liable to occur in a vertical direction. As a result, the whole showcase inclines, and when the door is closed, a lower part of the transparent door on the non-supported side thereof hits against a bottom frame for the door, which brings about the so-called “door lowering”.